Flexible track



Feb. 29, 1944. R. MAYNE 2,342,953

FLEXIBLE TRACK Filed July 12. 194i Patented Feb. 29, 1944 FLEXIBLE TRACKRobert Mayne, Akron, Ohio, assignor to The B. F.

Goodrich Company, New York, N. Y., a corporation of New York ApplicationJuly 12, 1941, Serial No. 402,123

14 Claims.

This invention relates to flexible track for use of vehicles of theself-laying track type.

Vehicles of the self-laying track or crawler type have heretofore beenprovided with tracks comprising a plurality of spaced-apart flexibletension elements such as metal cables held in spaced-apart relationtransversely of the track by cross-bars with which the cables areconnected for stress transmission by intervening rubber cushioningmaterial acting in shear stress between each bar and such cables so thatthe crossbars are resiliently secured to the cables in positions to actas driving members for operating the track. The cables and parts of thecross-bars have been embedded in a body of rubber-like materialpresenting one face for ground-engagement and its opposite face for thesupport of bogie wheels.

In one type of such track, the center region of the cross-bars areexposed, and the ends thereof with the cables are embedded in a pair oflaterally spaced-apart rubber bodies. In that type of track, it has beenfound, as shown in my Patent No. 2,107,490 of February 8, 1938, thatsidewise and torsional forces tending to deflect the track may beovercome by overlapping metal flanges mounted on the driving cross-barsin such center region and cooperating with each other to stiffen thetrack against deflection sidewise.

In another type of track, the cables and crossbars are embedded in asingle body of rubber cushioning material with the ends of the barsprojecting therefrom at the margins of the track for side-drivingengagement. The drive wheels used with this type of track may have adrum face for supporting the rubber body and sprocket teeth at eachflank thereof to engage wear membersand guide flanges mounted on theends of the cross-bars. In such an arrangement the spacing of thecross-bars may be relatively great So that overlapping guide platessecured to the ends of the cross-bars and simply sliding on each otherhave not always been effective in preventing lateral sway and torsionaltwist of the track. 7

The present invention aims to overcome the foregoing and otherdifliculties, and to provide an improved construction.

The principal objects of the invention are to provide for preventinglateral side sway and twist of the track under operating conditions,especially by means operating at the margins of the track, althoughfeatures of the invention are applicable to other locations than at themargins, to provide for accurate guiding of the track, and

to provide simplicity of construction and convenience of manufacture andassembly.

These and other objects will appear fromthe following description andthe accompanying drawing.

Of the drawing:

Fig. 1 is a side elevation of a vehicle drive having a track embodyingthe invention, parts being broken away.

Fig. 2 is a view on a larger scale showing a portion of the drive wheeland the track, parts being broken away.

Fig. 3 is'a plan view showing a portion of the track as seen from theinside face of the track.

Fig. 4 is a sectional detail View taken along line 44 ofFig. 2.

Fig. 5 is aside view of a modified construction.

In the illustrative embodiment the invention is incorporated in a trackcomprising longitudinally disposed wire cables held in spaced -apartrelation by driving cross-bars located at spaced intervals and cushionedfrom the cables by rubber-like material effective to transmit drivingforce by sheer stress in the rubber-like material. In accordance withthe invention overlapping arms are mounted upon the ends of the drivingbars for sliding engagement of the arms with each other, and the armsare loosely pinned to each other so as to stiffen the track againstlateral sway while the loose connections permit the cables to carry thestresses lengthwise of the track. In one form of the invention, the armsare integral with wear plates fitting over the ends of the driving barsand removable therefrom for replacement, which wear plates are adaptedto engage the sprockets.

Referring to the drawing, the numeral 10 designates a drive wheel of avehicle of the self-laying track type having a guide wheel H, and ibogiewheels l2, [3 about which the flexible track M is trained.

The track comprises a plurality of spaced-apart metallic cables [5 eachenclosed by a resilient rubber or other rubber-like covering IS, thecovered cables being held at intervals by cross-barv members l1, l8, andthe rubber between the cables and the cross bars is preferably adheredto both for transmission of the driving force by shear stress in therubber. The cables and crossbars are enclosed by a resilient body It ofrub- ?ber-like material, the ends-of the driving crossbars extendinglaterally beyond the body at the sides for driving'purposes.

Removable wear plates 20, 2| are secured about the ends of thecross-bars by bolts 22, 23 extending therethrough. The wear plates aregenerally of shallow U-shape as seen from the side, and the sides of theu engage the sprocket teeth We of the drive wheel ID in driving thetrack. Inwardly disposed guide flanges 25, 28, for engaging with thesides lb of drum Illa of the drive wheel ID and the guide and bogiewheels H, l2 and I3 may be integral with the wear plates.

For preventing side sway and torsional distortion of the track in use,longitudinally extending cars 21, 28 are provided preferably though notnecessarily integral with the wear plates. These ears extend forward andaft from the driving bars, and have such length as to overlap similarears on the next cross bars, which they engage in close sliding relationon vertically disposed faces thereof. Of the overlapping ears, one isformed with an aperture 29, preferably a longitudinally disposed slot,the other is provided with an outstanding pin 39, adapted to enter theaperture loosely. The arrangement is such that the ears slide upon eachother within the limits permitted by the pin-connections and restrictside-sway and twisting of the track, due to their close-slidingengagement and limited extensibility while driving tension is carriedsolely by the cables due to the loose 'fit of the pins 30 in theapertures, which are preferably located at the pitch line of the trackand sprockets to permit minimum clearance of the pins and apertures.

To provide for replacement of the tread of the track, removable treadshoes 40 may be secured on the tread face and may comprise metal plates4| having treads 42 of rubber-like material vulcanized thereto. Thebolts 22, 23 may have their heads embedded in and bonded to the rubberof the treads 42 and extend through the plates 4!, which are also bondedto the rubber, so that the tread shoes, the guide flanges 25, 26, andthe ears 2?, 28 are all secured togetherby a single bolt at each side ofthe track.

In the form of the invention shown in Fig. 5, the track body 50 ofrubber-like material encloses the tension cables held in spaced-apartrelation by cross-bars comprising pairs of crossbar members 52, 53having their ends extending from the rubber body as in the embodimentjust described. The wear plates 54 are mounted on the ends of thecross-bar members to engage the sprockets, but do not have the extendingears of the previously described form of the invention. Similar ears 55,56 are provided, however, on the metal plates 51 of the removable wearshoes secured to the bars, and have cooperating loose pin and slotconnections with the ears overlapping the ears of adjacent shoes insliding engagement. The pins are designated by the numeral 58 and theslots by the numeral 59. The pins are preferably mounted on the pitchline of the track so that minimum clearance about the pins is required.Suflicient clearance is provided, however, to permit the cables to carrythe entire tension load whereas the ears limit extensibility and act toprevent side-sway and twisting of the track.

In either form of the invention the resilient body of the track isadapted to contact with a plain driving drum and the sprockets flankingthe driving drum engage the Wear plates on the ends of the driving barsat the sides of the track. The interengaging ears for preventing sidesway and twisting of the track are located adjacent the sprockets inposition to clear the sprockets and the drum.

Variations may be made without departing from the scope of the inventionas it is defined by the following claims.

I claim:

1. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars associated with said means atregular spaced apart intervals and adapted to engage drive sprockets atthe sides of the track, and removable means comprising elementsdetachably carried by said cross-bars at the side of the track andengaging one another in sliding relation to limit lateral flexure of thetrack.

2. A self-laying track comprising longitudinally extending parallelstrands of wire tension elements, cross-bars attached at spaced apartintervals to the cables solely by intervening rubberlike material, abody of rubber-like material surrounding said elements and enclosingmid-portions of said bars and attached to said bars and elements by avulcanized bond, and removable means comprising detachable elementscarried by said bars at the sides of the track and engaging each otherin sliding relation to limit lateral flexure of the track.

3. A self-laying track comprising longitudinally extending reaches ofwire cable, a plurality of metal cross-bars mounted upon the cables atregular spaced-apart intervals and adapted to engage drive sprockets atthe sides of the track, and loosely interconnected detachable elementsremovably secured to the ends of said cross-bars at the margins of thetrack to limit lateral fiexure of the track.

4. A self-laying track comprising longitudinally extending reaches ofwire cable, a plurality of metal cross-bars mounted upon the cables atregular spaced-apart intervals and adapted to engage drive sprockets atthe sides of the track, and loosely interconnected detachable elementsremovably secured to the ends of said cross-bars at the margins of thetrack to limit lateral flexure of the track, said interconnectedelements comprising ears secured to successive cross-bars andoverlapping each other in sliding engagement, one of the ears of acooperating pair having an opening, and the other having a pin looselyengaging in the opening.

5. A self-laying track comprising longitudinal reaches of wire cable, aplurality of metal crossbars mounted upon the cables at regularspacedapart intervals and adapted to engage drive sprockets at the sidesof the track, tread shoes removably secured to the cross-bars, and meanscomprising removable elements detachably carried by said tread shoes andloosely interconheated in sliding relation to each other for limitinglateral flexure of the track, said means com prising ears on successivetread shoes overlapping each other in sliding engagement, one of saidears having an opening, and the other having a pin loosely engaging inthe opening.

6. A self-laying track comprising longitudinally disposed flexibletension means, a body of rubber-like material surrounding said tensionmeans, and removable means comprising detachable elements spaced alongsaid track at widelyspaced intervals and engaging one another in slidingrelation to limit lateral flexure of the track, one element of eachcooperating pair having an opening therein, and the other element of thepair engaging loosely in said opening.

7. A self-laying track comprising longitudinally disposed fiexibletension means, a. plurality of cross-bars associated with said means atspaced apart intervals along the track, and removable means comprisingdetachable elements on said cross-bars and engaging one another insliding relation to limit lateral flexure of the track, one element ofeach cooperating pair having an opening therein, and the other elementof the pair having a pin engaging loosely in said opening.

8. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars associated with said means atspaced apart intervals along the track, and removable means comprisingdetachable elements on said cross-bars and engaging one another insliding relation to limit lateral flexure of the track, one element ofeach cooperating pair having an opening therein, and the other elementof the pair having a pin engaging, loosely in said opening, some of saidelements having wheelengaging portions for guiding the track.

9. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars associated with said means atspaced-apart intervals along the track, a body of rubber-like materialenclosing said tension means and portions of said cross-bars, andremovable means comprising detachable elements on said cross-bars andengaging one another in sliding relation to limit lateral flexure of thetrack, one element of each cooperating pair having an opening therein,and the other element of the pair having apin engaging loosely in saidopening.

10. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars secured to said means solely byintervening rubber-like material and disposed at spaced-apart positionsalong the same, said cross-bars comprising sprocket-engaging means, andelements on said cross-bars at the margins of the track each comprisingportions extending into the spaces between adjacent cross-bars inoverlapping relation with extending portions of adjacent elements forlimiting lateral flexure of the track.

11. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars secured to said means anddisposed at spaced-apart positions along the same, said cross-barscomprising sprocket-engaging means, and elements on said cross-bars atthe margins of the track each comprising portions extending into thespace between adjacent cross-bars in overlapping relation with extendingportions of adjacent elements for limiting lateral flexure of the track,said elements comprising wheel-engaging guide extensions integraltherewith.

12. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars secured to said means anddisposed at spaced-apart positions along the same, said cross-barscomprising sprocket-engaging means, and elements on said cross-bars atthe margins of the track each comprising portions extending into thespace between adjacent cross-bars in overlapping relation with extendingportions of adjacent elements for limiting lateral flexure of the track,said elements comprising sprocketengaging wear plates integraltherewith.

13. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars secured to said means anddisposed at spaced-apart positions along the same, said cross-barscomprising sprocket-engaging means, and elements on said cross-bars atthe margins of the track each comprising portions extending into thespace between adjacent crossbars in overlapping relation with extendingportions of adjacent elements for limiting lateral flexure of the track,said elements comprising wheel-engaging guide extensions andsprocketengaging wear plates integral with said elements.

14. A self-laying track comprising longitudinally disposed flexibletension means, a plurality of cross-bars secured to said means solely byintervening rubber-like material and disposed at spaced-apart positionsalong the same, said cross-bars comprising sprocket-engaging means, andelements on said cross-bars at the margins of the track each comprisingportions extending into the space between adjacent cross-bars inoverlapping relation with extending portions of adjacent elementsfor'limiting lateral flexure of the track, said elements comprisingtread members integral therewith.

ROBERT MAYNE.

